Rf and sonic systems for preventing shoplifting of goods and unauthorized removal of capsules affixed thereto for protecting goods

ABSTRACT

Capsules or tags are affixed to a plurality of goods kept within a storage area, which capsules produce an alarm indication upon unauthorized removal of the goods through an exit area. The capsules or tags bear the designation &#39;&#39;&#39;&#39;Don&#39;&#39;t Remove-Electronic Alarm&#39;&#39;&#39;&#39; and contain first and second resonant devices and are affixed to the goods by means of an ordinary safety pin. The first resonant device actuates an article removal alarm when the goods pass through the exit area, whereas the unauthorized opening of the safety pin in an attempt to remove the capsule in the storage area to defeat the system enables the second resonant device which in turn produces a capsule removal alarm in the storage area and as a result a greater deterrent is present with respect to theft of the goods and special unwieldy fastening devices such as rivets, requiring special measures for application and removal are eliminated. Additionally small and/or delicate goods may be protected, which goods would not be protected owing to the aforementioned rivets or special fastening devices. Sonic systems which may or may not produce a capsule removal alarm operate preferably in the ultrasonic range. An extended range capsule is particularly well adapted for protecting goods stored in a warehouse.

Unite States atent 1 1111 3,713,133

Nathans Jan. 23, 1973 RF AND SONIC SYSTEMS FOR PREVENTING SHOPLIFTING OF[57] ABSTRACT GOODS AND UNAUTHORIZED Capsules or tags are affixed to aplurality of goods REMOVAL OF CAPSULES AFFIXED kept within a storagearea, which capsules produce an THERETO FOR PROTECTING GOODS alarmindication upon unauthorized removal of the [76] Inventor: Robert L.Nathans, 36 Stag Drive, goods through an exit area- The capsules tagsbear Bil] i ,M ,01821 the designation Dont Remove-Electronic Alarm andcontain first and second resonant devices and are [22] Filed 1971affixed to the goods by means of an ordinary safety [2]] Appl. No.:115,274 pin. The first resonant device actuates an article removal alarmwhen the goods pass through the exit 521 us. on. ..340/280, 340/224340/408 f x where "authmlzed Opening. the Safety [51] llnt. Cl. ..G(l8b13/18 pm m an attempt to remove the Capsule m the Storage [58] Fiend ofSeaIChU34O/Z8O 258 D 258 B, 258 C area to defeat the system enables thesecond resonant 340/224 405 device which in turn produces a capsuleremoval alarm in the storage area and as a result a greater [56]References Cited deterrent is present with respect to theft of the goodsand special unwieldy fastening devices such as rivets, UNITED STATESPATENTS requiring special measures for application and 3,665,448 5/1972McGlinchey etal ..340/258 c are eliminated" Additimany Small and/03.289.194 ll/l966 King ..340/280 delicate goods may be Protected which 2would 3,577,136 5/1971 w I I 23 not be protected owing to theaforementioned rivets 2,774,060 12/1956 Thompson... ..340/280 or specialfastening devices. Sonic systems which may 3,493,955 2/1 7 Minasy 1 4..340/224 or may not produce a capsule removal alarm operate 3,1 l7,277l/l964 Magondeaux ..340/408 preferably in the ultrasonic range. Anextended range P E J h w C M capsule is particularly well adapted forprotecting nmary xammero n a we Assistant Examiner-Glen R. Swann, lIlgoods Smred m a warehouse. AtrorneyRobert L. Nathans 13 Claims, 13Drawing Figures FL] I fi F-l i MICROPHONE/03 F-l ULTRASONIC M?) 704 106I07 I08 GENERATOR t ALARM INTERIVIITTENT ag F-l TUNED DRIVE AMP.

PAIENIEDmza I973 FLASH CAMERA SHEET 1 UF 2 FLASH CAMERA 4 LOUDSPEAKERGUARD STATION EXIT AREA DIRECTIONAL ANTENNA ARTICLE TAPE H RECO R DERREMOVAL CASHTER'S COUNTER 76 V 1/ PIVOTABLE R F SHIELDED CAPSULE BIN 32DETECTOR RWST W6 A& NU 08 SP EA RC sTDRE AREA! F 2 TANK 79 TANKf?PATENTEDJAH23I973 3.713133 SHEET 2 BF 2 F-l NT RROGAT H N I E 54 M4?)F]\ ,4 F DIAPHRAM7Z/80 SINGLE REBROADCASTER REBROADCASTERJ/REBROADCASTER 4 75 PRESSURE SENSITIVE SWITCH I REBROAD REBROAD- I CASTERCASTER RECHARGE TERMINALS ANTENNA 12/ TIN F/az FEE EXTENDED RANGE"WAREHOUSE" cAPsuLE 770 J MARTIN I W W 52 E-I RF. ARTIGLE AREAuLTRAsONIc TRANSCEIVER M I REMOVAL GENERATOR IO MC l 1 lg ALARM 7.9 AMROMNI" DIRECTIONAL :l ANTENNA 92 STORAGE F-2 R.F. CAPSULE AREA ULTRASONICTRANsGEIvER REMOVAL GENERATO 4 IsMc 97 ALARM K cAsHIER L 86 87 TUNEDINHIBIT 89 AMP GIRcuIT l0] 1 T N2 I MICROPHONE I03 F-I ULTRASONIC m4 I07I08 GENERATOR I INTER r v I T TENT [/02 F-I TUNED 0 FIG 6 RF AND SONICSYSTEMS FOR PREVENTING SI-IOPlLIFTING OF GOODS AND UNAUTHORIZED REMOVALOF CAPSULES AFFIXED THERETO FOR PROTECTING GOODS BACKGROUND OF THEINVENTION This invention relates to the field of theft preventionsystems and more particularly to such systems utilizing special tags orcapsules affixed to the goods.

It is estimated that shoplifting losses in the United States are wellover billion dollars per year, to say nothing of losses due to theftsfrom warehouses, etc. In the case of stores, numerous detectives, closedcircuit television, mirrors and other devices have been employed but thestaggering losses per year continue to increase.

Two clever electronic systems are now on the market which utilizespecial tags which are affixed to the goods. A midwestern manufactureris marketing an electronic system similar to the system covered by aU.S. Pat. to Thompson, No. 2,774,060, issued Dec. 11, 1956. In thissystem an article removal alarm circuit is situated at an exit area andcomprises an RF oscillator radiating at a carrier frequency of F-l. If ashoplifter carries a secreted article through the exit area, a specialtag containing a resonant circuit resonant at F-l loads the oscillatorto produce an exit alarm. These tags are affixed to goods, typicallydresses, by a plastic thread which is normally cut by the cashier uponpayment of the goods to remove the tag.

An eastern manufacturer is currently marketing a system similar to thesystem covered by a US. Pat. to Minasy, No. 3,493,955, issued Feb. 3,1970. A rigid 2" X 3" tag is riveted to the goods to be protected andcontains a rebroadcasting device which is actuated by an F-l RFinterrogation signal generated at the exit area and produces in responsethereto an F-2 RF signal which triggers an alarm in the exit area.

While these systems represent important initial steps in the productionof truly effective electronic theft prevention systems, they aresomewhat wanting in various respects. The shoplifters will readilyascertain that the tags of both systems are responsible for triggeringthe alarm. In the case of the Thompson systems it will be an easy matterto cut the plastic threads which couple the tag to the goods by meansof, for example, a toe nail scissors. The manufacturer of Thompson'ssystem suggests putting a dummy tag on the outside of the article andsecreting a live tag in an inconspicuous place on the article.Shoplifters will soon appreciate that all tags must be removed from thegoods before they are stolen and thus a serious drawback is seen inconnection with the current Thompson" system. While the rivets utilizedin the current Minasy system are more difficult to sever, it is believedthat the use of a small pair of pincers, particularly in the hands ofprofessional shoplifters and teenagers, will constitute an effectivecountermeasure. Additionally these rivets require the use of specialmachines for application and removal which is time consuming andsomewhat unwieldy. If one were to protect small and/or delicate itemssuch as hats, delicate lingerie, scarves, sweaters, shirts, hoisery,gloves, ties, belts, pocketbooks, fancy pillows, blankets, and objectsof art, the use of such rivets would be very unsuitable. Losses of theseitems are very heavy.

The use of the foregoing systems for protecting goods such as televisionsets and numerous other items of considerable value stored in awarehouse is even more questionable because a dishonest employee isfree, is an unpopulated warehouse area, to destroy the rivets, or othersturdy fasteners at his leisure by such tools as a pair of shears toremove the capsules before stealing the goods.

Thus it is desirable to provide a capsule which is quickly and easilyapplied to and removed from the goods to be protected without specialequipment or special techniques. It is also desirable to utilizeordinary safety pins to affix the capsules to the goods so that theabovementioned small and/or delicate goods may be readily protected. Itis particularly desirable to employ a protective capsule whichimmediately produces a capsule removal alarm (e.g. a chime or light) inthe storage area upon the opening or cutting of the safety pin. It is ofthe utmost importance to protect expensive goods in a warehouse by notrelying on brute force" fastening devices such as steel bands foraffixing the capsules to the goods, since such fasteners may be readilycut by a dishonest employee, by shearing, in unpopulated warehouse areasat his leisure. In the warehouse" market it is especially important toproduce a capsule removal alarm upon the removal of the capsule andagain it is desirable to quickly and easily afiix and remove thecapsules without special power tools. Particularly for warehouses whereit usually would be impractical to utilize numerous pickup antennas, anextended range capsule is desired. Additionally in view of the marketpotential for all of these alarm systems it is thought desirable todevelop other approaches which might be more inexpensive or reliablethan tags utilizing printed circuitry therein. It is also desirable toemploy ultrasonic generators, presently utilized in many facilities forintrusion alarm purposes, to activate theft prevention capsules havingmechanically resonant devices therein. Systems which will function inconjunction with very wide exit areas are also desirable.

SUMMARY OF THE PRESENT INVENTION In accordance with one embodiment ofthe inven' tion, a capsule is affixed to the goods by means of anordinary metallic safety pin, which safety pin enables one resonantdevice which coacts with a Thompson" type oscillator to produce acapsule removal alarm upon the unauthorized opening of the safety pin,the other resonant device contained within the tag or capsulefunctioning in the same manner as Thompson. In accordance with anotherembodiment of the invention, when the safety pin is opened, the Minasyrebroadcaster is enabled so as to produce a capsule removal alarm uponthe receipt of an interrogation signal in the storage area; therebroadcaster otherwise functioning to produce an article removal alarmin the exit area in the manner of Minasy. In accordance with anotherembodiment, the Minasy rebroadcaster is triggered by the application ofultrasonic energy thereto. Another embodiment employs extended rangecapsules particularly well suited for protecting goods stored inwarehouses. Further embodiments employ the use of sonic energy, alreadyavailable from installed intrusion alarms, which produces mechanicalresonance of devices within the capsules to actuate article removalalarms or capsule removal alarms or both.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesrelating to the invention will become apparent upon study of thespecific description taken in conjunction with the drawings in which:

FIG. 1 schematically illustrates the general layout of a store area;

FIG. 2 schematically illustrates a tag or capsule which contains a firsttank circuit for actuating an article removal alarm and a second tankcircuit for actuating a capsule removal alarm; W

FIG. 2A illustrates the first and second resonant device having a commonreactive element;

FIG. 2B is a top view ofa portion of the device shown in FIG. 2A;

FIG. 3 illustrates a capsule including two rebroadcasters;

FIG. 3A illustrates a variation of FIG. 3 which utilizes a singlerebroadcaster;

FIG. 4 illustrates a capsule useful in sonic embodiments;

FIG. 4A illustrates a variation of FIG. 3;

FIG. 43 illustrates a capsule having piezoelectric transducers;

FIGS. 5 and 5A schematically disclose theft prevention systems involvingsonic energy utilized in conjunction with RF energy;

FIG. 6 illustrates an alarm system employing sonic energy without RFenergy; and

FIG. 7 illustrates an extended range warehouse capsule including anactive and passive element.

SPECIFIC DESCRIPTION In FIG. 1, exit area 1 is disclosed having anarticle removal detector 2 coupled to alarm device 3 which couldcomprise a tape recorder for actuating a loudspeaker. Flash cameras 4and 4' may be employed if desired. Obviously, other alarm indicationdevices may be triggered by the article removal detector 2 such as alighted sign instructing the customer to have the inventory control tagremoved. Exit area 1 need not actually be the physical exit from thestore but could also consist of the area at the bottom of an elevator orescalator or an area in a larger store representing the boundary of agiven department.

FIG. 2 discloses a passive capsule which is utilized in conjunction withthe aforementioned Thompson US. Pat. No. 2,774,060 incorporated byreference herein. Article removal detector 2 would correspond to FIGS. 2or 3 of the Thompson patent and each resonant printed circuit shown inFIG. 2 may be similar to the resonant circuits of Thompson. The resonantcapsule or tag 6 disclosed in FIG. 1 is affixed to an object to beprotected such as dress 7 suspended from dress rack 8 shown in FIG. 1.As shown in FIG. 2, F-l tank circuit 9 is laminated within resonant tag11 and consists of inductor l2 and capacitor 13. If a shoplifter removesdress 7 having resonant capsule 6 attached thereto without paying forthe article and passes through exit area 1, the F1 tank circuit 9 willload the oscillator in article removal detector 2, all as described inthe aforesaid Thompson patent, thereby to activate the alarm indicationdevices. The cashier removes the capsule associated with the articlepaid for and inhibits the capsule removal alarm as explained in detailbelow. If the shoplifter pays for one item at cashiers counter 16 butsecretes another item bearing the capsule on her person, article removaldetector 17 will light a warning lamp so that countermeasures may betaken. In this special situation the warning lamp will only havesignificance if other customers are not at the cashiers counter withinrange of the article removal detector and the shoplifter has already hadthe first capsule removed from the article paid for. In this case thecashiers counter is the exit area. Article removal detector 17 at thecashiers counter is similar in construetion to detector 2.

Now let it be assumed that a shoplifter removes the capsule 6 from dress7 by either opening the safety pin or cutting the upper portion of thepin with a pair of wire cutters. The right hand portion of the capsuleof FIG. 2 has an F-2 tank circuit 19 laminated within the tag orotherwise positioned within the capsule. A safety pin 21 which isnormally in the closed position as illustrated will generally be openedby the shoplifter in an attempt to defeat the system by removing thecapsule. This pin does not have a lower segment unlike a regular safetypin and is electrically coupled across capacitor 23 of the F-2 tankcircuit 19. A safety pin may be easily affixed to a tag, etc. by passinga pair of resilient wires through the plastic tag sheet and which aresoldered to the tank circuit laminated therein. A safety pin head orequivalent catch is welded to one wire and the other may be bent over tobe resiliently held by the catch. Obviously many other approaches may beutilized to join a suitable fastener to a laminated tag or capsule uponmanufacture. Normally when the pin is closed, capacitor 23 is shortcircuited and tank circuit 19 will not resonate at the F-2 frequency.When the shoplifter opens pin 21 or cuts it with wire cutters, capacitor23 is now enabled and will complete the F-2 tank circuit. Capsuleremoval detector 26 of FIG. 1 is similar to article removal detector 2except that the oscillator therein oscillates at a frequency of F2rather than Fl as in the case of the article removal detector 2. Capsuleremoval detector 26 is preferably connected to at least one elongatedantenna several feet in length which may be vertically oriented within acircular dress rack or upon a pillar for example. In the alternative, ahorizontally oriented antenna(s) could be positioned along the length ofa counter or along the ceiling or under a rug. These antennas would becoupled to capsule removal detector 26. The aforementioned opening orcutting of safety pin 21 will immediately enable the F-2 tank circuit19, the oscillator within capsule removal detector 26 oscillating at F-Zwill be loaded, and capsule removal alarm indicators such as 27 and 28will be activated and thus unauthorized removal of resonant capsule 6 isimmediately detected, and swift countermeasures may be taken if desired,although the actuation of chimes, etc. should stop the shoplifter. Inaddition, an ordinary safety pin is utilized in the place of theaforementioned rivet devices or nylon threads currently being utilizedwhich greatly eases the task of attaching the capsules to the article tobe protected and the removal of such capsules by the cashier.Furthermore, the safety pins lend themselves to use in conjunction withsmall and/or delicate articles to be protected, unlike theaforementioned rivet devices as previously discussed.

In the more usual case of an honest customer, the dress is carried tocashiers counter 16. The cashier rotates pivotable lid 31 and drops thecapsule into an RF shielded capsule bin 32. The opening of lid 31actuates switch 33 which in turn inhibits a capsule removal alarm forthe brief period during which the lid is opened. This may be performedin a sophisticated system by activating an RF transmitter 34 whichtransmits an F-3 radio signal to activate inhibit signal detector 36which is tuned to an RF carrier having a frequency F-3. The inhibitsignal produced by this detection temporarily inhibits an alarmindication which would be otherwise produced by capsule removal detector26. The F-3 radio link could be eliminated in certain situations bydirectly wiring switch 33 to capsule removal detector 26 andparticularly where the capsule removal detector is positioned at thecashiers counter which is often feasible. Lid 31 is open for a 5 orsecond period which is necessary so that the cashier may open safety pin21 and deposit capsule of FIG. 2 within bin 32. The lid is thereafterclosed and the capsule removal detector 26 is again enabled. Methods ofpreventing the cashier from ringing up the sale without first removingthe capsule form no part of the present invention and will be coveredelsewhere.

In FIG. 2A, a capsule contains a single tank circuit 20. In thisconfiguration the aforementioned type of safety pin 21 is positionedwithin slot 41. A short circuiting control member 42 is coupled to theheel of the pin by coupling means 43 thereby to short circuit capacitor44 so that only capacitor 46 is coupled in series with the inductor.Under these circumstances the tank circuit of FIG. 2A will resonate atfrequency F-l thereby to activate article removal detector 2 or 17positioned in the exit areas as previously described. If the pin isopened by a shoplifter, capacitor 44 is no longer short circuited andtank circuit will resonate at F-2 and load down capsule removal detector26. This will also occur if the pin is cut by wire cutters because theheel of the pin will spring up. In this embodiment only a single tankcircuit may replace the twin tank circuit configuration of FIG. 2. Thismovable short circuiting element might also be practicable in the caseof a laminated tag having two holes in one of the outer sheets forreceiving the two legs of the short circuiting element 42. Of course thedouble capacitor" single tank circuit could be utilized in anarrangement such as described in connection with FIG. 2, i.e., nomovable short circuiting element. Also an inductor portion may be shortcircuited.

In accordance with another embodiment of the invention, the capsulesillustrated in FIGS. 3 and 3A may be utilized in conjunction with alarmdevices described in US. Pat. No. 3,493,955 of Minasy. Minasys capsulesinclude a rebroadcasting (reradiating) device such as illustrated inFIGS. 2 and 6 of his patent. The rebroadcasting device is laminatedwithin plastic tags which are riveted to the goods to be protected. InFIG. 2 of Minasy, an interrogation signal identification cir' cuitcomprises a resonant tank circuit 34 which is coupled to capacitor 44 ofMinasy via diode 46. When the tag is in the exit area, an F-linterrogation signal causes tank circuit 34 to resonate and a DC voltageis produced across capacitor 44 which in turn activates a transistorizedoscillator which resonates at a different frequency F-2. This F-2frequency is detected by an RF receiver positioned in the exit area andan article removal alarm indication is produced, all as explained inMinasys patent.

In the left hand portion of FIG. 3 the aforementioned signalidentification circuit is labelled 34' to correspond with tank circuit34 of Minasy. Likewise diode 46' corresponds with diode 46 in the Minasypatent. Rebroadcaster 51 shown in FIG. 3 includes circuitry shown in theupper portion of FIG. 2 of the Minasy patent. Thus, when the tag of FIG.3 is introduced into the exit area by a shoplifter, the Fl interrogationsignal radiated by article removal detector 31 producing theaforementioned DC voltage which in turn causes the rebroadcaster toretransmit an RF signal of frequency F-2 which produces the alarmindication as described in the Minasy patent. In other words, articleremoval detector 2 in the present embodiment corresponds to the Minasytransmitter 18 and receiver 26. In accordance with an embodiment of thepresent invention, a second rebroadcaster 51' is coupled to tank circuit52 via diode 53. A safety pin 54 having its lower segment removed, asshown, is electrically coupled across tank circuit 52. Capsule removaldetector 26 positioned at the cashier s desk or in the storage area issimilar to Minasys article removal detector but preferably, but notnecessarily, transmits an RF signal of frequency F-3 and tank circuit 52is tuned to the F3 frequency when safety pin 54 is opened. Thus inresponse to the unauthorized removal of resonant capsule 6 by ashoplifter, rebroadcaster 51' is activated and rebroadcasts an RF signalat frequency F4. Cap sule removal detector 26 in this embodiment has anRF receiver channel which is tuned to detect a radio frequency of F-4and a capsule removal alarm indication is produced as previouslydescribed. The laminated tag or capsule of FIG. 3 might utilize tworebroadcasting devices in each tag. In FIG. 3A, a single rebroadcasteris utilized having a tank circuit including two serially connectedcapacitors in the manner of FIG. 2A previously described. However, asingle rebroadcaster might share two separate input tank circuits. If ashoplifter introduces the tag of FIG. 3A into the exit area 1, safetypin 61 will be closed, capacitor 62 will be shunted and tank circuit 63will resonate at F-l to produce an article removal alarm. If theshoplifter opens the safety pin to discard the capsule, capacitor 62will now change the resonant frequency of tank circuit 63 so that itresonates at F-3 which is the capsule removal detector interrogationfrequency and a capsule removal alarm indication will be produced aspreviously described.

In the embodiments of FIGS. 2, 2A, 3 and 3A, or for that matter anyembodiment described herein, it might be feasible to have the exit areainterrogation signal and the store area interrogation signal both be ofthe same frequency if the dress rack area is sufficiently separated fromthe exit area (out of range) of if the directional antenna associatedwith article removal detector 2 does not pick up the capsule removal(rebroadcaster) signal. Thus with the embodiments of FIGS. 3 and 3A itis feasible to eliminate the unwieldy thumbtack rivets which are nowcommercially utilized in conjunction with the Minasy system. Ordinarysafety pins may be readily utilized to apply or remove the FIG. 3capsules. Obviously the movable short circuiting structure of FIG. 2Acould also be readily utilized in FIGS. 3 and 3A (although it isbelieved preferable to short circuit the capacitor or inductor byutilizing the conductivity of the safety pin directly). This is trueeven though a laminated tag is utilized rather than a slotted capsulesince holes could be drilled in the tag surface of the plastic tag sheetto receive the legs of movable short circuiting element 42. Theaforementioned embodiments could employ a rebroadcaster, including awristwatch" battery, such as shown in FIG. 7 of Minasy and in this casethe capsules could be considerably smaller than the 2" X 3" tags now incommercial use in the Minasy system as pickup coils of 7/8" in diameterwill suffice. See Col. 7 of Minasy. Such a small capsule having a safetypin would render Minasys system more practical in connection withaffixing the capsules to small and/or delicate items such as belts,hosiery, pocketbooks, sweaters, gloves, blouses, pillows, hats, delicatelingerie, etc. It is obviously impractical to utilize the riveted,rigid, 2" X 3" tags of Minasy on these items. It should be understoodthat ifa single tank circuit shown in FIGS. 2A and 3A is employed, eachtank circuit includes a first and second resonant device although eachresonant device has a common inductive and/or capacitive element.Obviously the safety pin could short circuit a portion of the inductorinstead of providing two capacitors.

Referring now to FIG. 4, another embodiment is disclosed which utilizesfirst and second resonant devices which mechanically resonate,preferably by directing sonic energy at said devices. A hollow capsule71 contains an F-l diaphragm 73 and an F-2 diaphragm 73 both of whichcould consist of thin metallic membranes supported by support elements74, 76 and 77. In the exit area, article removal detector 2 wouldcomprise an ultrasonic generator radiating sound at a frequency F-Itogether with an RF transceiver 79, (FIG. The F-l diaphragm 72 wouldhave a fundamental frequency of vibration equal to the frequency of thesound generated by ultrasonic generator 78. Typically F-l would be 20kilocycles which is for practical purposes beyond the hearing range. RFtransceiver 79 directs an RF carrier of say 10 megacycles at the FIG. 4capsule, positioned in the exit area, via directional antenna 81. Thistransceiver could take many forms as is well understood by those skilledin the art and would preferably, although not necessarilly, operate inthe continuous wave mode.

If the FIG. 4 capsule or tag is positioned in the exit area, ultrasonicgenerator 78 will cause diaphragm 72 to resonate. A portion of the RFenergy directed at diaphragm 72 by directional antenna 81 would bereradiated or returned to transceiver 79 which includes an ordinary FMreceiver. This returned RF signal will be frequency modulated at F-l bythe vibration of diaphragm 72 and would be detected and amplified by anF-l sharply tuned amplifier 82 coupled to the FM receiver output toproduce an input signal to article removal alarm circuit 83. In otherwords, alarm 83 would only be activated upon the receipt of an RF signalof 10 megacycles which is frequency modulated at the resonant frequencyof diaphragm 72.

In the storage area an F-2 ultrasonic generator 86 together with RFtransceiver 87 would function as capsule removal detector 26 of FIG. 1.The capsule of FIG. 4 with the safety pin closed would have no effect oncapsule removal detector 26 because the F-2 diaphragm 73 is dampened bya rubber damper 75 coupled to the heel of safety pin as shown in FIG. 4.Slot is similar to the slot described in connection with FIGS. 2A and 2Band functions to prevent tampering with the damper. Unlike directionalantenna 81, omnidirectional antenna 88 is utilized in connection withtransceiver 87 and again comprises an elongated wire or wires runningalong a counter or ceiling or vertically oriented conductor(s).

Now let it be assumed that the FIG. 4 capsule is removed by a shoplifterby opening pin 80 or cutting it. The heel portion of the pin pops up anddamper 75 permits F-2 diaphragm 73 to resonate at frequency F-2generated by ultrasonic generator 86 in the storage area. The 15megacycle RF signal frequency modulated at F-2 is detected as before andtuned F-2 amplifier90 actuates capsule removal alarm 89.

In the case of an honest customer, the cashier causes an inhibit signalto be applied to inhibit terminal 91 of gate 92 during the l0 secondperiod when the FIG. 4 capsule is removed from the dress being paid for.

The systems disclosed herein utilizing mechanically resonating devicescould, if desired, be utilized in the manner of the aforementionedsystem of Thompson and Minasy presently in use. That is, the capsulescould be riveted or otherwise affixed to the goods and only a singlediaphragm would be utilized for producing an alarm at the exit area.

In FIG. 6, a system is illustrated which does not employ RF energy. AnF-l ultrasonic generator 101 is controlled by intermittent driving means102 and produce bursts of sonic energy having a frequency F-l. Afrequency selective microphone 103 having a high Q would be positionedat the exit area to detect the sound reradiated by Fl diaphragm 72. Thissignal would be amplified and fed through inhibit gate 104 and would beamplified by sharply tuned amplifiers 106 and 107 to actuate alarmcircuit 108. Although the sound detected by microphone 103 would be aweak signal, it would be reamplified by a series of sharply tunedamplifiers which would amplify and pass the received signal only offrequency F-l. Just before the transmission of a particular burst ofultrasonic sound at F-l mono-stable multivibrator 111' is actuated andinhibit gate 104 prevents a signal picked up by microphone 103 frombeing applied to the tuned amplifier channel so that the transmittedsound burst has no effect on the alarm system. However, multivibrator l11 has an RC time constant such that it reverts back to its originalstate at a time after cessation of the first burst and before theinstant of transmission of the following burst, and thus sampling gate104 is opened during a time interval between bursts but is closed duringbursts. Input lead 112 of the multivibrator would be coupled tointermittent drive circuit 102 so that the multivibrator would betriggered just before an actual burst of sound is produced.

A second F-Z arrangement similar to the system of FIG. 6 could beutilized in the store area for capsule removal detection where the FIG.4 capsule is employed.

In FIG. 4A mechanically resonating transducers such as microphonecrystals could be utilized to power the aforementioned rebroadcasters.Crystal 121' would resonate at F-l in the exit area by directing an F-lsonic signal thereon while crystal 122' would resonate at the F-2interrogation signal generated by a capsule removal detector. A dampersuch as damper 75 previously described would dampen crystal 122', whenthe safety pin is closed. Again if rivets, etc. are utilized, the secondcrystal may be dispensed with. The AC electrical signal produced by thevibrating crystal would be rectified by the aforementioned diodes suchas 46' and 53 in FIG. 3 and would be applied across the previouslymentioned capacitor 44 of Minasy to power the rebroadcaster.

FIG. 4B is similar to FIG. 4 except that piezoelectric crystals 123' and124 are utilized in place of diaphragms 72 and 73. It appears that if anRF signal having a frequency equal to the resonant frequency of crystal123 were directed at the crystal that an oscillating electrical fieldgradient would be produced across the face of crystal 123 at theradiated RF frequency by virtue of tin foil members 126 and 127. In sucha case, the resulting vibration of the foil clad crystals could bedetected by microphone 103 as before. It is believed that F-2 diaphragm73 would be roughly the size of a dime because the calculated wavelength of a resonant body at 30 kilocycles is roughly l/3 of an inch.

In accordance with another embodiment of the present invention, FIG. 7illustrates a capsule which is believed to be particularly well suitedfor protecting articles stored in a warehouse. Because of the structuralcharacteristics of a large warehouse it may be impractical to provide alarge number of antennas coupled to one or more capsule removaldetectors since the support girders of a warehouse may be widelyseparated from one another or the ceilings might be quite high. Since awarehouse exit area may be relatively confined, an F-l tank 111 shown inFIG. 7 will serve to produce the exit area alarm as describedhereinabove. However, to extend the range of the capsules (i.e. thedistance from the capsule to the nearest capsule removal antenna), thecapsule of FIG. 7 utilizes a radiant energy source such as an active RFoscillator which becomes powered by a wristwatch battery, etc. upon theopening of the fastening means. Likewise such a capsule may be employedin shoplifting operations if the extended range is deemed useful.

Oscillator 112 is in series circuit relationship with battery 113 andswitch 114 which is spring biased to close by means of spring 116. Afastening device 118 prevents the switch from closing by means ofcoupling member 117 and thus when the capsule is affixed to the goods,the series circuit remains open, power is not applied to RF oscillator112, and a signal is not radiated by antenna 121. Thus under normalcircumstances, no power is being drained from power source 113. Ifdesired, the RF oscillator may generate a carrier having a frequencyindicative of the location of the protected article, to facilitatecounter measures against the theft or theft pattern. In the alternative,or additionally, the oscillator may be modulated by a signal having acharacteristic such as frequency pulse repetition rate, etc. to performthis function.

Upon the opening of fastener 118 or the attempted destruction of thefastener or coupling means 117,

spring 116 closes the power circuit and an RF signal is radiated byantenna 121. This signal may be detected by an RF receiver tuned to thecarrier frequency of oscillator 112, the receiver in turn being coupledto a threshold device as described hereinabove in connection with FIGS.5 and 6. Obviously the receiver could have a detector and filter channelfor identifying the predetermined modulation of the RF carrier if it ismodulated.

Particularly in the case of protecting a warehouse, containing expensivearticles, the manufacturer of this capsule could afford to make acapsule having at least a partially hollow configuration for housing oneor more wristwatch batteries for generating an RF capsule removal signaldetectable at a range of say yards. The shell of the capsule could befabricated of a tough plastic material and the capsule could be pottedby standard techniques so that it would be very difficult for awarehouse employee to destroy the capsule in attempting to mash it. Inorder to further deter such mashing, a wide area pressure activatedswitch could be formed upon the inner surface of the plastic shell whichwould independently power the oscillator regardless of the state of thefastening means. Such a pressure sensitive switch 120 is coupled inparallel with switch 114 as shown. Such switches are known in the artand form no part of the present invention.

Since the battery is not normally being drained, it would probably lastfor at least a couple of years. However, a pair of recharging terminals122 are optionally provided for externally recharging the battery. Anasymmetrical conductor, which could comprise a diode 123, is coupledbetween one of the recharging terminals and battery 113 as shown. If anattempt is made to short circuit the battery by externally shorting theterminals, such an attempt will be ineffective since diode 123 presentsa very high impedance in the reverse direction of current flow.

It is also believed that the capsule of FIG. 7 may be utilized forextended range shoplifting applications since the power source isnormally not being drained. It is apparent that since tampering with thefastener 118 will activate the spring biased switch it appears that suchfastening devices such as steel bands, rivets, etc. can be replaced by asimple light weight device such as, or somewhat similar to, a safety pinwhich does not require special tools and procedures for application andremoval. As stated previously in connection with other embodiments,rebroadcasters, diaphragms, crystals, etc. could replace F-l tankcircuit 111. A self triggering blocking oscillator could generate a 10millisecond burst of RF every 2 seconds to further conserve power ifdesired as the oscillator would only be radiating 0.5 percent of thetime.

It is to be understood that the term exit area" includes any area withinwhich one desires to activate an alarm if a capsule is present. Forexample, article removal detector 17 at the cashiers counter would be anexit area for detecting a secreted article positioned at the cashierscounter. The term alarm indicator" encompasses any device which producesa signal which is useful in connection with apprehending a shoplifter ora thief in another protected area such as a warehouse. The term resonantdevice encompasses electrical tank circuits, diaphragms, transponders,

rebroadcasters, crystals or other devices having periodic ornon-periodic modes of vibration, e.g. blocking oscillators. The termcapsule encompasses any support member supporting the devices describedsuch as tags, hollow or semi-hollow shells (potted or not) or integratedcircuits positioned within conventional lead frames.

In summary, the present invention illustrates a plurality of systemswhich differ from the commercially marketed systems of Minasy andThompson and may be adapted to produce capsule removal alarm indicationsand may be utilized in conjunction with an ordinary safety pin ratherthan rivets, etc. which require special machines for application andremoval and which are inappropriate for protecting small and/or delicatearticles.

While the present invention has been described in specific termshereinabove it is to be understood that the invention in its broadestsense is limited only by the following claims: 7

1. A method of deterring the unauthorized removal of goods through agiven exit area by attaching a capsule to each of the goods to beprotected, said capsule including a resonant device for mechanicallyoperating at at least one predetermined frequency of vibrationcomprising the steps of:

a. causing said resonant device to mechanically resonate at apredetermined frequency of vibration at said given exit area bydirecting sonic energy thereat;

b. detecting the mechanical resonance of said resonant device at saidgiven exit area by detecting at least a portion of wave energyreradiated by said resonant device; and

c. producing an article removal alarm indication in response to thedetection of said wave energy reradiated by said resonant device at saidgiven exit area.

2. The method of claim 1 wherein the step of detecting the mechanicalresonance of said resonant device includes selectively detecting aresonant frequency of sound generated by said vibrating resonant device.

3. The method of claim 1 wherein said step of causing said resonantdevice to mechanically resonate at said predetermined frequency includesdirecting sonic energy at the capsules attached to said goods withinsaid given area, said sonic energy having a frequency which inducesmechanical vibration of said resonant device.

4. The method of claim 3 wherein said step of detecting the mechanicalresonance of said resonant device includes directing radio frequencyenergy at said capsules and detecting the modulation of the returnedportion of said radio frequency energy produced by the vibration of saidresonant device.

5. The method of claim 3 wherein the step of detecting the mechanicalresonance of said resonant device includes selectively detecting aresonant frequency of sound generated by said vibrating resonant device.

6. The method of claim 5 wherein sonic energy is directed at saidcapsules in bursts and the selective detection of the sound generated bythe vibrating resonant device is performed between said bursts.

7. A method of deterring unauthorized removal of an article from astorage area through an exit area comprising the steps of:

a. attaching a capsule to a protected article stored within said storagearea, said capsule including a first and second resonant device, eachresonant device including a vibrating body which mechanically resonatesin response to the receipt of sonic energy;

. causing said first resonant device to resonate within said exit areaby directing sonic energy at said capsule generated outside of saidcapsule;

c. detecting the resonance of said first resonant device within saidexit area and producing an article removal signal in response to thedetection of the resonance of said first resonant device in said exitarea but not in said storage area;

. interrogating said second resonant device in said storage area bydirecting sonic energy at said capsule generated outside of said capsulecapable of causing said second resonant device to resonate;

e. inhibiting the resonance of said second resonant device when saidcapsule is attached to said article to be protected;

f. enabling the resonance of said second resonant device upon theunauthorized removal of said capsule from said article to be protected;

g. detecting the resonance of said second resonant device produced bysaid unauthorized removal; and

producing a capsule removal indication signal in response to the lastnamed step.

8. The method of claim 7 wherein said vibrating body is a piezoelectricbody and resonance thereof is produced by directing sonic energythereon.

9. An externally activated capsule specifically designed to deterunauthorized removal of an article from a storage area through an exitarea upon being activated at said exit area, said capsule being attachedto said article and said capsule comprising:

a. a support member;

b. a first passive resonant device positioned upon said support member;

0. a second passive resonant device comprising a vibrating body whichmechanically resonates at a particular frequency positioned upon saidsupport member;

d. fastening means for attaching said support member to said article tobe protected; and

e. control means including a damper for damping said vibrating body whensaid fastening means assumes a first state and for undamping saidvibrating body when said fastening means assumes a second state.

10. The capsule of claim 9 wherein said vibrating body comprises a thinmetallic diaphragm.

1 l. A device for use in a theft prevention system for preventing theunauthorized removal of goods from a given area, said device beingattached to said goods within said given area and comprising:

a. a mechanical diaphragm designed to mechanically vibrate at a givenfrequency of vibration;

b. coupling means for attaching said mechanical diaphragm to said goodsto be protected; and

c. control means positioned between said coupling means and saidmechanical diaphragm for selectively damping the vibrations of saidmechanical diaphragm when said coupling means assumes a first state andfor undamping the vibrations of said mechanical diaphragm when saidcoupling means assumes a second state.

12. An externally activated capsule specifically designed to deterunauthorized removal of an article from a storage area through an exitarea upon being activated at said exit area, said capsule being attachedto said article and said capsule comprising:

a. a support member;

b. a resonant device positioned upon said support member for coactingwith an article removal alarm device associated with said exit area forproducing an article removal alarm when said capsule is positioned atsaid exit area but not within said storage area;

c. a radiant energy source positioned upon said support member forgenerating a radiating signal capable of being detected by a capsuleremoval alarm device;

d. a power source for activating said radiant energy source;

e. a fastener for coupling said capsule to said article to be protected;

f. power control means for causing said power source to activate saidradiant energy source upon the actuation of said fastener; and

g. a pair of recharging terminals coupled to said power source to enablethe external recharging of said power source.

13. The capsule as set forth in claim 12 further including a devicehaving an asymmetrical current conducting characteristic coupled betweenone of said terminals and said power source for enabling externalcharging thereof and at the same time for preventing external shortcircuiting of said power source by an individual tampering with saidcapsule.

1. A method of deterring the unauthorized removal of goods through a given exit area by attaching a capsule to each of the goods to be protected, said capsule including a resonant device for mechanically operating at at least one predetermined frequency of vibration comprising the steps of: a. causing said resonant device to mechanically resonate at a predetermined frequency of vibration at said given exit area by directing sonic energy thereat; b. detecting the mechanical resonance of said resonant device at said given exit area by detecting at least a portion of wave energy reradiated by said resonant device; and c. producing an article removal alarm indication in response to the detection of said wave energy reradiated by said resonant device at said given exit area.
 2. The method of claim 1 wherein the step of detecting the mechanical resonance of said resonant device includes selectively detecting a resonant frequency of sound generated by said vibrating resonant device.
 3. The method of claim 1 wherein said step of causing said resonant device to mechanically resonate at said predetermined frequency includes directing sonic energy at the capsules attached to said goods within said given area, said sonic energy having a frequency which induces mechanical vibration of said resonant device.
 4. The method of claim 3 wherein said step of detecting the mechanical resonance of said resonant device includes directing radio frequency energy at said capsules and detecting the modulation of the returned portion of said radio frequency energy produced by the vibration of said resonant device.
 5. The method of claim 3 wherein the step of detecting the mechanical resonance of said resonant device includes selectively detecting a resonant frequency of sound generated by said vibrating resonant device.
 6. The method of claim 5 wherein sonic energy is directed at said capsules in bursts and the selective detection of the sound generated by the vibrating resonant device is performed between said bursts.
 7. A method of deterring unauthorized removal of an article from a storAge area through an exit area comprising the steps of: a. attaching a capsule to a protected article stored within said storage area, said capsule including a first and second resonant device, each resonant device including a vibrating body which mechanically resonates in response to the receipt of sonic energy; b. causing said first resonant device to resonate within said exit area by directing sonic energy at said capsule generated outside of said capsule; c. detecting the resonance of said first resonant device within said exit area and producing an article removal signal in response to the detection of the resonance of said first resonant device in said exit area but not in said storage area; d. interrogating said second resonant device in said storage area by directing sonic energy at said capsule generated outside of said capsule capable of causing said second resonant device to resonate; e. inhibiting the resonance of said second resonant device when said capsule is attached to said article to be protected; f. enabling the resonance of said second resonant device upon the unauthorized removal of said capsule from said article to be protected; g. detecting the resonance of said second resonant device produced by said unauthorized removal; and h. producing a capsule removal indication signal in response to the last named step.
 8. The method of claim 7 wherein said vibrating body is a piezoelectric body and resonance thereof is produced by directing sonic energy thereon.
 9. An externally activated capsule specifically designed to deter unauthorized removal of an article from a storage area through an exit area upon being activated at said exit area, said capsule being attached to said article and said capsule comprising: a. a support member; b. a first passive resonant device positioned upon said support member; c. a second passive resonant device comprising a vibrating body which mechanically resonates at a particular frequency positioned upon said support member; d. fastening means for attaching said support member to said article to be protected; and e. control means including a damper for damping said vibrating body when said fastening means assumes a first state and for undamping said vibrating body when said fastening means assumes a second state.
 10. The capsule of claim 9 wherein said vibrating body comprises a thin metallic diaphragm.
 11. A device for use in a theft prevention system for preventing the unauthorized removal of goods from a given area, said device being attached to said goods within said given area and comprising: a. a mechanical diaphragm designed to mechanically vibrate at a given frequency of vibration; b. coupling means for attaching said mechanical diaphragm to said goods to be protected; and c. control means positioned between said coupling means and said mechanical diaphragm for selectively damping the vibrations of said mechanical diaphragm when said coupling means assumes a first state and for undamping the vibrations of said mechanical diaphragm when said coupling means assumes a second state.
 12. An externally activated capsule specifically designed to deter unauthorized removal of an article from a storage area through an exit area upon being activated at said exit area, said capsule being attached to said article and said capsule comprising: a. a support member; b. a resonant device positioned upon said support member for coacting with an article removal alarm device associated with said exit area for producing an article removal alarm when said capsule is positioned at said exit area but not within said storage area; c. a radiant energy source positioned upon said support member for generating a radiating signal capable of being detected by a capsule removal alarm device; d. a power source for activating said radiant energy source; e. a fastener for coupling said capsule to said article to be protected; f. poweR control means for causing said power source to activate said radiant energy source upon the actuation of said fastener; and g. a pair of recharging terminals coupled to said power source to enable the external recharging of said power source.
 13. The capsule as set forth in claim 12 further including a device having an asymmetrical current conducting characteristic coupled between one of said terminals and said power source for enabling external charging thereof and at the same time for preventing external short circuiting of said power source by an individual tampering with said capsule. 